Process for the production of sodium hydrosulphide and valuable byproducts



'35 barium sulphide black ash phide in the .so ution.

UNITED STATES an anvonn. or. CLEVELAND,

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PBQOESS FOR THE PRODUCTION O1 7 No Drawing.

The present invention relatesto a process v barium carduced and whereby sodium hydrosulphide,

bonate and barium sulphate are pro from barium sulphide, carbon dioxid, 6 sodium sulphate.

. :Heretofore sodium. hydrosulphide has been commonl manufactured by treating sodium sulphi e with hydrogen sulphide according to the reaction:

This process, while commercially successful, isnot entirely satisfactory since it involves among other objectionable features the generation an absorpt on of large quantities of poisonous hydrogen sulphide gas, operations which are both hazardous and ex ensive. li/Iy investigations have led to the (118- covery of a process for the product1on of sodium of hydrosulphide whereby the ob ectionable generation and absorption of the hydrogen sulphide is largely or entirely eliminated and a considerable economy 1n carrying out the process is effected by the 7 production ofthe valuable btyrproducts,

barium sulphate and barium car onate.

Various other advantages tion will appear from a consideration of the following description of its preferred embodimnt.

A' solution of about 22 B. and contaming the chemical equivalent of about 16% of Bus silch as may be obtained by leachlng in the well-known way is charged into closed steel bubblers or equivalent apparatus and gassed with 'carbon dioxid, preferably of relatively high purity, until substantially of the bari- 40 um content of the solution corresponding to the barium hydroxid content thereof is precipitated as .barium carbonate. The reactions involved in the process thus far described probably are as follows:

That is, in the solution of the barium sulhide in water it dissociatesinto barium y'droxid and barium hydrosulphide and the carbon dioxid treatment transforms the barium h droxid into the insoluble carbonate thus eav'in only the barium hydrosulof my inven-.

By subsequent treat-' OHIO, ASSIGNOB TO TIIE GRASSELLI OHEMI- OHIO, A CORPORATION 01 OHIO.

somum nrnnosutrnmn am: vALuAiBLu arrnonuc'rs.

Application filed February 8, 1926. .Serial No. 88,838.

ment of the reaction mixture the precipitated barium carbonate is recovered and the barium hydrosulphide is converted into sodium as will described hereinafter.

In connection with the carbon dioxid treatment described it is noted that the inhydrosulphide and barium'sulphatc,

vention is not limited to the use of the precise quantity of carbon dioxid specified since under certain conditions it may be found to be advisable to use a lesser or greater quantity. The. use of a smaller quantity of carbon dioxid redu ces the yield of barium carbonate and also tends to produce a sodium hydrosulphide product containing sodium sulphide or requiring treatment with hydrogen sulphide to convert the sodium sulphide into ydrosulphide, whereas the use of more carbon dioxid while increasing the yield of barium carbonate and reducing the sodium sulphide content of the sodium hydrosulphide product or reducing the hydrogen sulphide requirements of the process also reduces the yield of sodium hydrosulphide and may, if carried too far, result in the liberation and loss of h drogen sulphide.

The slurry containing arium carbonate and barium hydrosulphide resulting from the carbon dioxid treatment is separated, preferably by filtration. The barium carbonate press cake, after washin is re-slurried with water, refiltered, drie and milled and is then ready to market. The filterate of barium lg d'rosulphide containing say 11.5% of Ba H), is treated with a suflicient quantity of sodium sulphate or salt cake solution to'precipitate the barium as barium sulphate by a reaction corresponding with the following equation:

and sodium hydrosulphide resulting from this reaction is also preferably separated by filtration. The barium sul hate press cake,

after washing, is re-slurre with water containing suflicient sulphuric acid to neutralize any alkaline'salts present and convert the slimy precipitate into. one having a dense crystalline structure. then re-filtered and prepared in t e usual manner forthe.market as blanc fix.

The sodium hggrosulphidesolution, that is, the filtrate m the barium sulphate This preci itate is ings from the factory prices.

slurry to which referably is added the washarium sulphate precipitate, under the conditions described will have a sodium hydrosolphide content of about 5.6%. This solution me. be used directly or worked up in any suitabl; Way. A preferred procedure is to concentrate the solution to about sodium 'hydrosulphide and then, since the solution produced as described ordinarily contains an excess of sodium sulphide amounting to about 10%, it may be gassed with hydrogen sulphideto convert this sodium sulphide to the h drosulphide.

Among the advantages 0 .the process in addition to those already mentioned are the lower cost and higher quality of the sodium hydrosulphide than sodium hydrosul hide produced as usual by the reduction 0 salt cake and treatment of the resulting sodium sulphide with hydrogen sulphide. The barium sulphate andbarium carbonate produced are sufficiently pure for commercial use and the relative uantities thereof produced are such that bot may be disposed of at satismay be replaced by strontium sulphide or by other sulphides having substantially similar properties. This and similar modifications fall within the sec e of my invention unless they are preclude by the terms of the appended claim. It is'understood that the invention is not limited to any particular theory regarding the chemical reactions in! volved.

I claim:

In a process for the production of sodium hydrosulphide the steps which consist in treating a solution of barium sulphide with carbon dioxid in a variable amount, up to about one-half the chemical equivalent of the barium content of the solution, depending upon the amount of sodium sulphide desired in the product, and separating the resulting barium carbonate from the solution.

In testimony'whereof, Iafiix my signature.

EARL BURNARD ALVORD. 

